The present invention relates to a single point detection current sensor and, more particularly, to an interference correction type single-point detection current sensor for multiple busbars.
A method of measuring the amount of current in a contactless way in a panel board and a switch board includes a method using a current transformer and a method using a magnetic sensor. A method using a circular core as in a current transformer is a method of measuring the amount of current through induced electromotive force according to an induced magnetic flux that is formed in the core itself. Such a method has relatively small interference with other power lines, but requires a great installation space because an induced magnetic flux is formed while circulating the core. Furthermore, such a method is vulnerable to a mechanical deformation attributable to vibration or a mechanical shock and has a safety problem in installation and between control systems in an environment in which insulation has not been provided as in a busbar.
In contrast, the magnetic sensor method is a method of disposing sensors capable of measuring a magnetic flux, such as hall sensors, on the periphery of busbars, directly measuring the amount of a magnetic flux, and converting the measured amount into the amount of current (refer to Korean Patent Application Nos. 10-2009-0075419 and 10-2012-0028306). A single-point detection type current sensor for obtaining information about current that flows at a single point location of wire or a busbar using a magnetic sensor as described above is advantageous in that the installation of equipment is easy, but has a problem in that the sensor itself is greatly influenced by environments, such as a temperature and the distance, and a problem in that an error of a measured value is severely generated due to severe interference between lines in an environment in which multiple busbars connected to a high-power load are concentrated.
The inventor of the present invention has developed a current sensor having improved measurement accuracy by removing interference occurring between busbars while maintaining the advantage of the magnetic sensor method in order to measure the amount of current in an environment in which a plurality of busbars is concentrated (multiple busbars).